SCHENECTADY, N.Y. (AP) — An early morning fire swept through a two-story wood frame house in eastern New York on Thursday, killing four people, including three children, authorities said.

A fourth child was injured and taken to a burn unit at Westchester Medical Center.

The fire in Schenectady, just west of the capital of Albany, broke out shortly after 4 a.m. It was the third fire of the night in the city of about 66,000 people and struck shortly after firefighters fought another blaze about a half-mile away.

The investigation will look for any connections between the two nearby fires, but Fire Chief Michael Della Rocco said they are believed to be unrelated.

Two adults and four children lived in the upstairs unit, Della Rocco said. The father was killed along with three of his children. Della Rocco said they haven’t been able to locate the mother, who was not in the house at the time of the fire.

The building burned quickly and completely largely because it was made in a late 19th- and early 20th-century building style known as “balloon construction” in which studs run from the ground to the roof without the fire-breaks required by modern codes, Della Rocco said.

The house, gray with maroon trim, was tucked closely between two other two-story homes on a residential street where many of the houses are two-family. The second-floor was gutted and the roof gone. The fire curled siding on the house next door, separated by a narrow alley barely the width of a car and filled with charred debris.

City fire investigators were working with state and federal agencies to try to determine the cause. Della Rocco said the building will be condemned and demolished.

Krystal Ashline knew the family and said the children ranged in age from about 11 months to 7 years.

“The kids were great kids,” she said. “My kids played with them. He was a really good father. He was the one who mainly took care of the kids.

“It’s a tragedy,” she said. “It just broke my heart.”

Shane Conway, who lives on the first floor of the house, told The Daily Gazette that he awoke around 4:30 a.m. to the shouts of his stepfather’s girlfriend.